Refrigerator using solid carbon dioxide



July 1, 1958 F. E. HAZARD REFRIGERATOR USING SOLID CARBON DIOXIDE 2 Sheets-Sheet 1 Filed Oct. 5. 1955 'INVENTOR. F. E. HAZARD FIG ATTORNEY United States Patent 2,840,995 REFRIGERATOR USING SOLID CARBON DIOXIDE Frederick E. Hazard, Chicago, Ill. Application October 3, 1955, Serial No. 538,236 17 Claims. (Cl. 62-167) This invention relates to a refrigeration system and more particularly to improvements in a system employing bunkers utilizing a solid refrigerating medium such as the well known Dry Ice or solid carbon dioxide. Still more particularly the invention features the use of the gas produced during sublimation of the Dry Ice for two purposes; e. g., insulation of the container in which the system is used, and as a preserving or protective medium for certain types of perishables constituting the lading of such container, having reference to the use of the arrangement in a refrigerated transport vehicle or car or even in stationary storage.

It is an important object of the invention to utilize the insulation properties of the gas produced from the sublimation of the refrigerating medium, and it is a further object to use the preservative qualities thereof in certain types of lading. Still another object is the provision of control means for diverting or cutting off at will that portion of the gas allotted to the gas distributor, which functions, when supplied with gas, to distribute'the gas to the lading. Further features of the invention reside in the use of panels in the form of double-walled structures that afford cells for containing the gas as an insulator, in the mounting and arrangement of such panels in a container having such length as to require two or more of the panels in end-to-end relation, in the provision of pressure relief means for exhausting gasses above a predetermined pressure, and in a novel arrangement of gas and fluid outlets from the bunkers, as well as certain features relating to the use of plural bunkers and heatexchange means,'such as cold walls, panels, coils or the like, insulating panels and gas distributor means selectively associated with the bunkers.

It is another principal object of the invention to provide a novel and improved bunker structure in which the surface area contact of the solid refrigerant and the heat-exchange surfaces is increased and maintained, particularly during the sublimation of the medium, which object is accomplished by providing the bunker with a sloping floor and a wall perpendicular thereto, whereby the block of refrigerating medium rests on the floor and has at least one full side in face-to-face contact with the wall. It is another object to provide such bunker with a floor sloping in opposite directions, as from a medium zone, each floor section having a perpendicular wall. Other objects reside'in the combination and arrangement of parts and components thereof as will appear in detail in the following specification and accompanying sheets of drawings, the several figures of which will be described below. i

Figure 1 is a schematic perspective showing a preferred arrangement of bunkers, heat-exchange means, insulating panels and gas distribution panels.

Figure 2 is an enlarged fragmentary plan view, partly in section.

Figure 3 is a fragmentary section as seen generally along the line 3-3 of Figure 2.

Figure 4 is an enlarged fragmentary view as seen along the line 4-4 of Figure 2.

Figure 5 is a section as seen along the line 5-5 of Figure 2.

Figure 6 is an enlarged section as seen along the line 6-6 of Figure 2.

Figure 7 is a section taken along the line 7-7 of Figure 1.

Figure 8 is a schematic view, on a reduced scale, illustrating, by way of example, a refrigerator car in which the invention is embodied.

Figure 8, in the illustration of a refrigerator car, represents a container 19 to be refrigerated and adapted to carry a shipment or lading of any one of various types, notably perishables, which, of course, require refrigeration during transport or during storage during hold-over periods. This car is merely exemplary, for it is obvious that the system may be used in other portable as well as stationary containers. The car shown has a floor 12, a top or roof 14, opposite ends 16 and 18 and opposite sides 20 and 22 (see Figs. 2 and 5). Each side has the usual doorway, only one of which is visible at 24. The improved system includes, in the example shown, a pair of bunkers 26 and 28, one at each end of the car; although fewer or more could be used. In a manner that will be brought out below, the bunkers supply refrigeration for heat-exchange means, here shown, by way of example only, as a set of cold walls 30 along the car side 20, and a second set of cold walls 32 along the car side 22 (see Figure 1), and also supply gas for two sets of insulating means or panels 34 along the roof of the car, and two sets of gas distributors or panels 36 also along the roof of the car and preferably flanked by the insulating panels 34. Access to the bunkers is preferably by way of covers or hatches 38 and 40, respectively, which may be hinged as shown or otherwise provided for convenience in opening and closing; although, access could be from the front or either side. Each bunker is adapted to contain a suitable refrigerating medium of the solid type, the best type known at the present being the socalled Dry Ice, a representation of which appears schematically at D in Figure 5. As is known, Dry Ice of the carbon-dioxide type sublimes as distinguished from melting like water ice and produces carbon-dioxide gas, which gas has certain insulation and food preserving properties, both of which are advantageously exploited by the present invention, as will readily appear below.

Since the bunkers 26 and 28 may be identical, and since the system may be used on a lesser scale with only on bunker, only the bunker 26 will be described in detail, it being understood that the other bunker has similar parts and characteristics. To this end, then, the bunker 26 is made up of wall means, shown herein simplified form as including the associated portions of the car end and side walls 16, 20 and 22, the roof or top wall 14, a transverse upright partition wall 42 and a bottom partition wall 44, the covers 38 providing, of course, part of the top wall. Included in or surrounded by the wall means, with the exception of the top and covers, is a double-walled reservoir 46 constructed of metal or other material having a high rate of heat conductivity. This reservoir has four upright walls 48, 5t), 52 and 54 and a double section floor here illustrated as comprising right and left hand floor sections 56 and 5'8 which slope outwardly and downwardly from a central or median zone defined by a ridge 60; although, a reversal of the slopes is within the scope of the present invention, if the wall sections 52 and 54 are centrally disposed. The interior portions or wall sections of the side walls 52 and 54 are respectively perpendicular to their associated floor sections 56 and 58. In this manner, the lowermost cakes or blocks of Dry Ice have full-face contact with the floor sections and the side blocks have full-face contact with the wall sections, insuring the maximum in heat abstraction as respects a suitable heat-exchange fluid contained 'in and circulated through the reservoir 46. See Figure in particular. As will be seen in that figure, as well as in Figure 3, the reservoir does not extend across the top of the bunker and the bunker is therefore a typical box-like structure in which a chamber 62 is afforded for containing the Dry Ice and for confining the carbondioxide gas produced as the Dry Ice sublimes; that is to say, the interior chamber is gasand fluid-tight as respects the double walls 48, 59, 52' and 54 and the double floor sections 56 and 53 so that the gas and fluid are physically separated volumes; that is there is no gas or fluid interchange between the chamber 62 and the reservoir 46; although, the chamber has a gas outlet 64 for purposes to presently appear. The reservoir has a fluid inlet 66 and a fluid outlet 68, which will also be described in detail below. As best seen in Figure 5, the gas outlet is recessed above the reservoir 46 to avoid perforating the rear wall 50 of the reservoir and the fluid inlet and outlet terminate within the reservoir and therefore have no communication with the chamber 62.

The reservoir, by means of the fluid inlet 66 and outlet 68 and associated fluid lines 76 and 72, comprises part of a fluid circulating system including the set of cold walls 30, which walls may be double-walled panels, coils or any other structure adapted for the purpose of carrying the fluid so that the fluid abstracts heat from the container 10, returns to the bunker 26' via the inlet 66, is cooled and leaves via the fluid outlet 68. A typical thermostatic valve 74 is shown as in controlling relation to the inlet 66. The other set of cold walls 32 is associated in a similar manner with a similar reservoir etc. in the other bunker 28. The arrangement could be revised to suit other requirements, at least as respects the relationship of the heat-exchange or cold wall sets to the individual bunkers; although, in a container of the length of the conventional refrigerator car, the present arrangement has many advantages.

In the preferred embodiment of the invention herein disclosed, there are two sets of insulating panels and two sets of gas distribution panels. There are four panels 34a, 34b, 34c and 34a in one set of insulating panels and four panels 34e, 34f, 34g and 3411 in the other set. There are two panels 36a and 36b in one distributor set and two panels 36c and 36d in the other set. The panels 34a, 34b, 34c, 34d, 36a and 36b are supplied with gas from the gas outlet 64 of the chamber 62 of the bunker 26. The other panels of the sets 34 and 36 are supplied from the gas chamber in the other bunker 28. Since the details are the same, a description of one will suflice for the other.

As best shown in Fig. 2, the gas outlet64 is furnished with a cross fitting 76 from which lines 78 lead to the panels 34a and 34b and from which a line 80, having a shut-ofl valve 82, leads to the panel 36a. The panels in the sets 34 and 36 may be of the same detailed construction, with one exception to be presently noted, apart from size. As shown here, each panel is a double-Walled structure seamed about its marginal edges, with intermediate portions of the walls brought together and secured to each other by any Well known process to afford a plurality of islands X among which are cells Y, the ends of the panels affording manifolds Z so that the cells in each panel are interconnected. As respects the panels 34a and Me, the manifolds Z at one end are connected to the gas outlet branch lines 78 and the'manifolds at the opposite ends are connected respectively to the manifolds Z of the panels 34b and 34d by flexible conduits 84. Hence, if the panels in the set 34 are individually secured to the underside of the car roof, the flexibility of the conduits 84 accommodates weavingand other relative distortion of the panels. The distributor panels 36a and 36b have their proximate manifolds interconnected by flexible conduits 86 for the same purpose, the front manifold of the panel 36a being connected to the valved line 80. The panels in the set 36, being narrower than those in the sets 34 may have only a single island X and two cells Y, but the important exception in the sameness of the panels lies in the perforation at 88 (Figure 6) of the under wall in each panel in the set 36, which perforations afford means by which carbondioxide gas may be let into the lading. The panels 36 could obviously be perforated pipes. The valve 82 controls the line and may be turned on or off, depending upon whether gas distribution to the lading is or is not desired. Some perishables are benefited by the gas and others are not. A similar shut-off valve 90 controls the gas from the bunker 28 to the panels 36c and 36d, which valve is associated with branch lines of the type shown at 767880. The valves 82 and 90 may be multiflow valves for cutting out gas flow to the panels 34 in the event the requirement for gas to the panels 36 is higher than that for the panels 34. The numeral 92 designates a thermostatic valve for the control of refrigerant from the bunker 28 to the set of heat-exchangers or cold walls 32.

Because of the pressure rise in the gas in the cells Y of the panels in the sets 34, one of the panels in each set is provided with a pressure relief valve, one being shown at 94 for the panel 340 and another at 96 for the panel 34h.

In the use and operation of the system, the bunkers are supplied with Dry Ice as already described. Sublimation of the Dry Ice, incurs in a strictly thermosyphonic system circulation of fluid in the cold plate sets and produces gas in the bunker chambers, as 62 for the bunker 26; although, circulating pumps or the like may be employed. With the valves 82 and 90 open, part of this gas enters the distributor panels 36 and escapes via the perforations 88 into the lading and part of the gas enters the set of insulating means or panels 34. If the lading is of the type that would suffer from the gas, the valves 82 and 90 are cut off, but the panels 34 still receive a supply of gas. In the case of sublimation that produces carbon-dioxide gas, the gas that would otherwise be wasted is used to fill the cells in the panels 34, thus constituting these panels as one of most effective insulating means known. This effect is produced as an adjunct to the refrigerant circulation in the sets of heatexchangers or cold wall panels 30 and '32, and one supplements the other, although the fluid in the panels 30 and 32 never interchanges with the gas in the panels 34 and 36.

The improved bunker construction, mainly because of the sloping floor sections, secures the maximum heatexchange between the Dry Ice and the reservoir walls, and the entire system obtains the utmost in efliciency and initial low cost. Other features and advantages as well as modifications in the structure and arrangements disclosed will undoubtedly occur to those versed in the art, all of which may be achieved without departure from the spirit and scope of the invention.

What is claimed is:

1. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a pair of bunkers, one at each end of the container, each bunker having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, and each wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigcrating medium; each chamber having agas outlet through its wall means and each reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; a plurality of fluid-circulating heat-exchangers alongcertain walls of the poptainer, certainof said heat-exchangers being connected to the fluid inlet and outlet of one reservoir andother of said heat exchangers being connected to the fluid inlet and outlet of the other reservoir; a plurality of insulating means adjacent to at least another Wall of the container and defining gas-receiving cells, certain of said cells being connected to the gas outlet of one bunker chamber and other of said cells being connected to the gas outlet of the other bunker chamber; and pressure relief valve means connected to certain of the cells and extending externally of the container to relieve excess gas pressure in the cells.

2. For a container having opposite end Walls, opposite side walls and a top wall, a refrigerating system comprising: a pair of bunkers, one at each end of the container, each bunker having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, and each Wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigerating medium; each chamber having a gas outlet through its wall means and each reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; a plurality of fluid-circulating heat-exchangers along certain walls of the container, certain of said heat-exchangers being connected to the fluid inlet and outlet of one reservoir and other of said heat exchangers being connected to the fluid inlet and outlet of the other reservoir; a plurality of insulating means adjacent to at least another wall of the container and defining gas-receiving cells, certain of said cells being connected to the gas outlet of one bunker chamber and other of said cells being connected to the gas outlet of the other bunker chamher; and gas-distributor means within the container and including a gas-transfer connection to the gas outlet of at least one bunker chamber, said connection having a. shut-off valve therein, and said distributor means including a gas discharge means for discharging gas into the container.

3. The invention defined in claim 2, in which: the gas distributor means runs centrally of its wall of the container from one bunker to the other, and the insulating means flanks said distributor means at each side thereof.

4. The invention defined in claim 3, in which: the gas distributor means includes a plurality of end-to-end double-walled panels, each aflording a gas chamber and at least one wall of each panel is perforated to afford the gas discharge means; and the insulating means comprises a plurality of end-to-end double-wall panels affording the cells.

5. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker at one end of the container andhaving wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, and said wall means including in heat-exchange relationship to said chamber a reservoirfor containing a fluid from which heat is abstracted by the solid refrigerating medium; said chamber having a gas outlet through its wall means and said reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; fluid-circulating heat-exchanger means along certain of the walls of the container and connected to the fluid inlet and outlet of said reservoir; insulating means adjacent to at least another wall of the container and defining gas-receiving cells, certain of said cells being connected to the gas outlet of the bunker chamber; and pressure relief valve means connected to certain of the cells and extending externally of the con tainer to relieve excess gas pressure in the cells.

6. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker at one end of the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, and said wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigerating medium; said chamber having a gas outlet through its wall means and said reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; fluid-circulating heat-exchanger means along certain of the walls of the container and connected to the fluid inlet and outlet of said reservoir; insulating means adjacent to at least another wall of the container and defining gas-receiving cells, certain of said cells being connected to the gas outlet of the bunker chamer; and gas-distributor means within the container and including a gas-transfer connection to the gas outlet of the bunker chamber, said connection having a shut-off valve therein, and said distributor means including a gas discharge means for discharging gas into the container.

7. The invention defined in claim 6, in which: the gas distributor means runs centrally of the container from said bunker to the opposite end of the container, and

the insulating means flanks said distributor at each side thereof.

8. The invention defined in claim 7, in which: the gas distributor means includes a plurality of end-to-end double-walled panels, each aifording a gas chamber and at least one wall of each panel is perforated to afford the gas discharge means; and the insulating means comprises a plurality of end-to-end double-wall panels afiording the cells.

9. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker at one end of the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, and said wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigerating medium; said chamber having a gas outlet through its wall means and said reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; fluid-circulating heat-exchanger means along certain of the walls of the container and connected to the fluid inlet and outlet of said reservoir; and self-contained insulating means adjacent to and substantially coextensive with at least another wall of the container and Wholly separate from the container walls and defining gas-receiving cells, certain of said cells being connected to the gas outlet of the bunker chamber.

10. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker in the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, said wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from, which heat is abstracted by the solid refrigerating medium; said chamber having a gas outlet through its wall means and said reservoir having a fluid inlet and a fluid outlet and being sealed against gas and fluid interchange with the chamber; a plurality of upright fluid-circulating heat-exchangers respectively adjacent to the side walls of the container and connected to the fluid inlet and outlet of the reservoir; and a plurality of self-contained horizontal gasreceiving and insulating means adjacently below and substantially coextensive with the top of the container and connected to the gas outlet of the bunker chamber.

11. The invention defined in claim 10, in which the insulating means includes a first gas-receiving cell having a controlled outlet leading externally of the container and a second gas-receiving cell having a controlled outlet leading to the interior of the container.

12. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker in the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, said wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigerating medium; said chamher having a gas outlet through its wall means and said reservoir being sealed against gas and fluid interchange with the chamber; and gas-distributor means within the container and connected to the gas outlet of the chamber, said distributor means having a substantial area relative to a container wall being provided with a plurality of gas discharge outlets, dispersed throughout said area for discharging gas into the container.

13. For a container having insulated opposite end walls, insulated opposite side walls and an insulated top wall, a refrigerating system comprising: a bunker in the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, said wall means including in heat-exchange relationship to said chamber, a reservoir for containing a fluid from which heat is extracted by the solid refrigerating medium; said chamber having a gas outlet through its wall means and said reservoir being sealed against gas and fluid interchange with the chamber; insulating means within the chamber and defining a gas-receiving cell separate from said container walls; gas distributor means including a plurality of gas discharge means exiting into the container; and gas transfer means connecting the insulating means and the distributor means in parallel to the gas outlet of the bunker chamber, said transfer means including a valve for selectively cutting off chamber gas from and admitting chamber gas to the distributor means while maintaining admittance of gas to the insulating means.

14. For a container having opposite end walls, opposite side walls and a top wall, a refrigerating system comprising: a bunker in the container and having wall means defining a chamber adapted to contain a solid refrigerating medium of the type characterized by sublimation and the production of a gas, said wall means including in heat-exchange relationship to said chamber a reservoir for containing a fluid from which heat is abstracted by the solid refrigerating medium; said chamher having a gas outlet through its wall means and said reservoir being sealed against gas and fluid interchange with the chamber; and insulating means within the container and including double-walled panel means juxtaposed relative to a. container wall and defining a gasrecciving cell connected to the gas outlet of the chamber.

15. A refrigeration bunker, comprising: an insulating structure of box-like construction having a floor and upright marginal walls, said floor having a horizontal upper surface and said marginal walls respectively having vertical inner surfaces rising from the upper surface of the floor; a box-like container disposed within the insulating container and affording a chamber for holding Dry Ice, said container having a double-walled floor and doublewalled upright walls forming a reservoir for containing a fluid refrigerant from which heat is abstracted by the Dry Ice, said container floor having a horizontal lower plate resting on the upper surface of the insulating floor and each container wall having an upright outer plate engaging the inner surface of the associated insulating wall, said container floor further having an upper plate out of parallel with said lower plate and sloping outwardly and downwardly toward at least one of the container upright walls to cause the Dry Ice to gravitate in that direction, and the container upright wall toward which the Dry Ice is thus caused to gravitate having an inner plate out of parallel with its associated outer plate and perpendicular to said container floor upper plate for full face contact with the Dry Ice.

16. The invention defined in claim 15, including: conduit means extending through one of the insulating walls for conducting from said chamber gas produced by sublimation of the Dry Ice.

17. The invention defined in claim 16, in which: the portion of the insulating wall through which said conduit means passes is offset from the associated container wall so that said conduit means is clear of said associated container wall.

References Cited in the file of this patent UNITED STATES PATENTS 1,696,651 Slate Dec. 25, 1928 1,864,259 Small June 21, 1932 2,019,296 Eubanks Oct. 29, 1935 2,039,334 Nagy May 5, 1936 2,044,609 Hedlund June 16, 1936 2,104,685 Wilson Jan. 4, 1938 2,187,569 Henney Jan. 16, 1940 2,187,9l3 Quinn Jan. 23, 1940 2,332,027 Swanson Oct. 19, 1943 2,440,098 Keller Apr. 20, 1948 

